Visual design refresh

![image](https://f.cloud.github.com/assets/3093635/1636416/426d5f64-57cd-11e3-8121-8ab240e5ded3.png)
* navigation :grey_exclamation: 
* changed color scheme to be more sane and nice :green_heart: 
* changed type faces too :grin: 
* replaced screenshots with nicer ones :gem: 
* responsive :trophy: 
* added a cute logo which helps conversion, maybe :panda_face: